How to Read & Identify Bearing Number

Bearing numbers serve a valuable purpose in the classification of bearings. 

They provide at-a-glance information about typical usage, durability, and suitability for specific applications.

Regardless of the brand, and even for custom bearings, if you have a grasp of the standard bearing number meaning, you can accurately identify the bearing you need. 

It's crucial to note that bearing model designations aren't universally standardized and can vary by brand. For ease of reference and comparison, we have developed a special Bearing Cross Reference.

Next, we will present a more unified perspective on bearing codes, conforming to the widely accepted industry standards.

Basic Structure of Bearing Numbers

Typically, a bearing number is composed of three distinct parts: the prefix, the Basic Designation, and the suffix. 

Take the NTN radial ball bearing code 'TS2- 6206 x1 LLB N C3 P5/2AS' as an example:

'TS2' represents the prefix, meaning “Heat stabilized up to 320°F (160°C)”; 

'6206' is the Basic Designation - Digit Identification of Bearing;

'X1', 'LLB', 'C3', 'P5', 2AS' are the suffixes.

For some bearings, they are exclusively identified with numeric codes, devoid of any prefix or suffix, such as the bearing “6206”.

Some bearings only have suffixes, such as “6206 LLB C3 P5”.

Bearing Number Components

Prefixes

Prefixes primarily indicate specific components of a bearing and can also identify various bearing variants. Let's take the NTN prefix as an example.

In terms of thermal stability:

In terms of materials:

For SKF, its deep groove ball bearing code prefixes such as:

Digit Identification of Bearing

First Digit Identification of Bearing

The initial digit in bearing numbers carries substantial significance as it often denotes the type of a bearing. It is instrumental in identifying the bearing's core design.

For instance, in '6206', the first digit “6” refers to ‘Single row deep groove ball bearing’. 

The following table lists various types of bearings alongside their type codes.

Second Digit Identification of Bearing

The second digit in bearing numbers typically signifies the bearing series. It reflects the robustness of the bearing, with certain numbers indicating light, medium, or heavy series. Consequently, this digit provides valuable insight into the bearing's ability to handle different load conditions.

For instance, in '6206', the 2nd digit “2” refers to ‘Light’.

The table provided below represents the different bearing series alongside their corresponding numeric codes.

Third and Fourth Digit Identification of Bearing

The third and fourth digits in bearing numbers are of great significance as they typically represent the the inner diameter (ID) of the bearing in millimeters. They provide crucial information about the bearing's fit with the shaft it will be mounted on.

Please see the table below.

The bore size in bearing numbers ranges from 0 to 3, signifying 10 to 17 mm.

For numbers over '03', the bore size is calculated as 5 times the value represented by the 3rd and 4th digits in the bearing number. 

For example, in “6206”, '06' corresponds to the bore size, and thus, “06” translates to a bearing bore size of 6*5=30 mm.

In scenarios where the fourth digit is absent from the bearing number, the third digit stands for the bore size.

For instance, for a bearing size of '234', the number '4'—equivalent to 4mm—denotes the bore size.

Suffixes

Suffixes, signify different designs or variants that deviate from the original or current basic design. For instance, Shielded and Sealed Bearings have different suffixes.

For “6206 LLB”, “LLB” stands for a bearing with non-contact rubber seals.

The following table presents some common bearing suffixes for seals or shields.

Different brands have different expanded suffixes.

In terms of NTN, please see the table below.

For SKF, see the following table.

Besides seals or shields, there are other suffixes, such as cage design, materials, heat treatment, accuracy, clearance, preload, quiet running, stabilization, lubrication, as well as other special specifications.

Tips for Decoding the Bearing Number Meaning

• Leverage Resources: Use manufacturer guides and online tools for identifying different types of bearings.
• Understand Structure: Comprehend the significance of prefixes, the Basic Designation, and suffixes.
• Avoid Assumptions: Verify bearing numbers across manufacturers - don't assume they're identical.
• Check Errors: Be mindful of typos, as they can alter bearing specifications.
• Ask When Uncertain: Consult with experts if unsure about a bearing number.